Non-oxidative intercalation and exfoliation of graphite by Bronsted acids


KOVTYUKHOVA N. I. , WANG Y., Berkdemir A. , CRUZ-SILVA R., TERRONES M., CRESPI V. H. , et al.

NATURE CHEMISTRY, cilt.6, ss.957-963, 2014 (SCI İndekslerine Giren Dergi) identifier identifier identifier

  • Cilt numarası: 6 Konu: 11
  • Basım Tarihi: 2014
  • Doi Numarası: 10.1038/nchem.2054
  • Dergi Adı: NATURE CHEMISTRY
  • Sayfa Sayısı: ss.957-963

Özet

Graphite intercalation compounds are formed by inserting guest molecules or ions between sp(2)-bonded carbon layers. These compounds are interesting as synthetic metals and as precursors to graphene. For many decades it has been thought that graphite intercalation must involve host-guest charge transfer, resulting in partial oxidation, reduction or covalent modification of the graphene sheets. Here, we revisit this concept and show that graphite can be reversibly intercalated by non-oxidizing Bronsted acids (phosphoric, sulfuric, dichloroacetic and alkylsulfonic acids). The products are mixtures of graphite and first-stage intercalation compounds. X-ray photoelectron and vibrational spectra indicate that the graphene layers are not oxidized or reduced in the intercalation process. These observations are supported by density functional theory calculations, which indicate a dipolar interaction between the guest molecules and the polarizable graphene sheets. The intercalated graphites readily exfoliate in dimethylformamide to give suspensions of crystalline single- and few-layer graphene sheets.